Tightening a nut onto a bolt causes the bolt to stretch slightly. Much like a spring, the bolt resists this stretching, and its tendency to return to its natural state creates clamping action between, say a cylinder head and a manifold, or two pieces of sheet-metal housing.

It is critical to the component’s operation that the amount of tension created holds the parts together strongly enough to prevent their separation by outside forces such as the machine’s vibration, the load stress generated during operation, gasket creep, temperature fluctuations, and more. Too much torque, however, can stretch the fastener too much, to the point where it chips, breaks, or yields. Bolts and screws are rated by their “proof load” – how much tension they can withstand before they fail. As a rule of thumb, torque a “clamp load” (also known as “preload”) 75 percent to 90 percent of the proof load is optimal.

It’s easy to get confused when deciding whether to use a fully or partially threaded metric bolt for a particular assembly. Often, people simply use whatever bolt is available—assuming that if it fits, it’s probably close enough. However, it’s important to bear in mind that the size of a bolt hole is just one small part of the overall engineering that goes into a completed assembly.

How a bolt grips and how loads are distributed by the bolt, are critical factors in the strength of a union. Bolts grip and distribute differently, depending on variables such as thread pitch, head size and, of course, whether the bolt is fully or partially threaded. To ensure proper grip and resistance to breakage, it’s important to use a bolt that meets the original engineering specs.

Over time, metric fasteners can wear out, work loose, or break off. The more a piece of equipment is used, the more often metric fasteners will need to be replaced. With a 24/7 schedule, few industries are as hard on equipment as the medical industry. Everything from handcarts to ultrasounds are used and relied on constantly within the medical industry by rotating shifts of employees.

This puts a lot of strain on medical equipment, and makes repairs a frequent problem. Finding the right metric fasteners is key to getting medical equipment up and running again.

With all of the nuts in the world, it can be hard to figure out which one is right for your assembly. To help you along with selecting the proper product for your project, here’s a brief rundown of some of the most common metric nuts and their applications.

Metric All Metal NutsThese general purpose nuts are commonly found on cars, farming machinery, and in metal working industries. They’re very tough, reusable, and provide a solid connection.

Spring is in the air, and that means a lot of people will be dusting off their bicycles and heading out for long rides. The question is, are those bikes ready for another season of two-wheel adventures? Worn or loose fasteners and bolts can turn a pleasant ride into a nightmare. Before hopping on your bike, make sure it’s up to the task.

A bicycle is made up of a surprising number of parts. All of those parts are held together by various metric bolts and washers. If any one of those metric fasteners are worn or incorrectly sized, parts can come loose and you may be at risk for injury. Here, we’ll take a look at some of the most important systems of a bicycle, and the most common metric fasteners used by those systems.

Some things have been around so long that it’s easy to forget that there was a time they didn’t exist. These items fill their need so easily and so completely that we can’t imagine a time when people had to get by using other means. One of these items is the “kep” nut. This nut has been around for nearly a century, and many assemblers couldn’t imagine life without it.

A Little History
The kep nut was invented in 1923 by Shakeproof Screw and Nut Lock Company. The “kep” in kep-nut comes from the name Sha(kep)roof. Now owned by Illinois Tool Works (ITW), the kep nut revolutionized manufacturing and assembly just as assembly lines were taking off. Continue reading

When it comes to keeping things together, engineers, designers, and builders overwhelmingly choose metric machine screws. They’re in everything from kitchen cabinets to deep-space probes. Given the wide variety of things put together with metric machine screws, it’s no surprise that there is such a wide variety of metric screws to choose from. Learn about the different types of metric machine screws and when to use them.

The establishment of the International Organization for Standardization (ISO) is based on the need to facilitate international trade by promoting development of universal standards. Having been in place for over a decade now, the ISO 9001:2008 Certification is a universal method used by both customers and companies to control the quality of output.

It is a framework of business management ensuring continued improvements in all aspects of the business. The external assessment on a regular basis ensures maintenance of these business practices.

Most people would be amazed by the amount of information that can fit on the head of a bolt. As you may already know, information about the diameter, length, and thread pitch of a fastener can often be found on its head. However, there’s a lot of other information that manufacturers put on the head of a bolt that you may not know about. That information can make a big difference in the type of bolt you choose for your application. Here, we’ll look at some of the markings, and what they mean in terms of real-world applications

Whether you’re a part-time hobbyist or a seasoned mechanic, there comes a time when you have an unidentified hole, bolt, or screw. To finish your assembly, you need to know exactly what size fastener you have, or what size fastener you need. The “guess and test” method can damage the threads on the fastener and in the hole. Worse yet, you could end up with something that seems to fit, but isn’t really the right size. When that happens, mechanical failure becomes a real risk.

Fortunately, screw thread callouts are a standardized system for determining the size, thread pitch, and length of a machine screw or hole. With this information, you can quickly get all of the information you need to ensure that your fastener fits perfectly into your assembly.